As well as searching the document's general text you can place additional information into the document such as:
Title : Allows a title for the document. All the documents created with the PDF-XChange, will have this title by default unless edited later.
Subject: Enter the subject of the documents. As with the Title value, all documents will have this subject until updated subsequently again.
Author: The Document Author, may an individual or Company etc.
Keywords: Enter here the keywords which can significantly enhance search returns through large PDF document volumes.
Creator: Specify here the creator of the document. This can be the same as the Author value or a department etc within your organisation.
Producer: This field denotes the software producing the PDF files (PDF-XChange) and its version.